(a) Field of the Invention
The present invention relates to a wind power generator or wind-driven electric generator, specifically having a rotation axis changeable depending on the direction of wind power.
(b) Description of Prior Art
Conventionaly, there has been proposed a propeller-type generator wherein a plurality of propeller blades are radially extending from power shaft which is horizontally and rotatably supported. However, as such prior propeller-type wind power generator cannot enlarge each width of the propellers, its propeller diameter must be enlarged instead, thus being large-sized in general. Further, such fixed propeller blades are prone to break due to a strong wind.
Whilst, there is also proposed another propeller-type wind power generator having rotatable blades whose angles to a plane perpendicular to the power shaft is variable, wherein a computer can control such angles, depending on wind power. However, according to such control by computer, the apparatus will have relatively complicated construction as well as late reaction to wind, particularly a strong gust of wind, thus sometimes causing the blades to break.
Further, there is also proposed another wind power generator in Japanese Patent Laid-Open No. 62-113868, wherein a plurality of blades are rockably supported by each spoke radially provided on a power shaft, and each blade is biased toward a closing direction with respect to the plane perpendicular to the power shaft with the use of springs. The wind power generator has mounting rings of connectors protruding from the blades, which are axially supported by cylindrical spokes, each having one end of a coil spring fixed to the spoke and the other end fixed to the blade. Namely, when the wind is not so strong, the blades will be inclined to the above-mentioned plane owing to the springs (i.e., pitch angle becoming large), and the blades will be rotated together with the power shaft by the wind. On the other hand, when the wind becomes strong to a certian degree, the blades will become nearly perpendicular to the plane owing to the wind power against the springs (i.e., pitch angle becoming small), thus preventing the damage to the blades.
However, according to the prior art, as the setting of spring force needs fine adjustment, it is difficult to stabilize the movement of the blades. For example, if the spring force is a little less than its optimized value, the pitch angle of the blades will become smaller, thus preventing efficient generation of electric power. On the other hand, if the spring force is a little more than the value, the blades will become difficult to be rotated by the wind, thus resulting in possible damage to the blades.
As above described, according to the prior wind power generator having angle-variable blades which are supported by spokes and loaded with springs, as the connectors fixed to the blades are axially supported by the spokes and one end of the coil spring is fixed to the spoke, while the other end thereof to blades, the adjustment of the spring force must be carefully done, thus making it difficult to stabilize the movement of the blades.